Details

S0ix is the name of Intel's implementation of Low Power Idle states as described
in ACPI spec via LPIT, and SPMC. It can be thought of as a hardware managed
suspend state whereby all software needs to do is sufficiently idle the system,
and hardware will go into the lower power state until woken by a specified set
of events.

Newer laptops with Intel CPUs prefer a sleep state known as s0ix (where x can be
1, 2, or 3). s0ix entry and benefits are explained in the patches found on
github.

Test Plan

Test suspend to idle on a machine supporting s0ix. Use residency
counters to determine if successful.